As the use and complexity of networks continues to grow, it becomes increasingly important to provide efficient, intuitive methods for monitoring and managing networks. Consequently, methods and devices have been developed for mapping the connections between the devices on a given network (i.e. the "topology" of the network). A visual representation of the network may be generated based on such topology maps. Such visual representations assist network administrators to pinpoint problems that occur on the network.
In the past, the topology of a network has been constructed based on ID/port databases maintained on each of the hubs or concentrators in the network. Such a strategy is described, for example, in U.S. Pat. No. 5,226,120 issued to Brown et al. on Jul. 6, 1993. According to this strategy, each device on a network periodically generates an identification signal. Each identification signal contains information identifying the device which originally generated the identification signal. When a concentrator receives an identification signal, a medium access controller (MAC) in the concentrator stores data indicating (1) the device from which the identification signal originated, and (2) the specific port on which the identification signal was received, in a ID/PORT database. The concentrator rebroadcasts the identification signals it receives, and its own identification signal, to all other concentrators on the network, which build their own ID/PORT databases. A network management station on the network periodically polls each concentrator to access the information contained in the various D/PORT databases, and from this information constructs a database of the topology of the network.
As the size of a network increases, the efficiency of the method by which the network management station constructs the overall topology of the network becomes increasingly important. An inefficient topology mapping process may cause significant delays between the time a network manager requests the display of a topology map and the time the topology map is actually displayed. The practical value of topology maps as network monitoring tools decreases with the length of time required to generate the maps.
In light of the foregoing, it is clearly desirable to provide a method and apparatus for quickly and efficiently mapping the physical topology of a computer network. Further, it is clearly desirable to provide an apparatus and method for generating the physical topology of a network which is compatible with current network standards and takes advantage of the information available in networks which conform to those standards.